NEW YORK — The public can't see the testimony a grand jury weighed before declining to indict a white police officer in the chokehold death of an unarmed black man, an appeals court said Wednesday, citing longstanding reasons for grand jury confidentiality.

"The public interest in disclosure was outweighed by the dangers inherent in violating the secrecy of the grand jury proceeding," judges in the state Supreme Court Appellate Division's Second Department wrote.

Grand juries have operated for centuries behind closed doors, for reasons ranging from shielding witnesses to protecting the rights of targets who don't get charged. Transcripts are rarely disclosed — with some notable exceptions, as after an officer wasn't indicted last year in the killing of unarmed teenager Michael Brown in Ferguson, Missouri. Wednesday's ruling echoed a lower-court decision in the case of Eric Garner, whose fatal encounter with police was recorded on video.

But city Public Advocate Letitia James, the New York Civil Liberties Union and the Legal Aid Society said they would appeal. They're seeking the transcripts, detailed descriptions of evidence and other documentation in the Garner case, which was fueled by the online video and led to widespread protests about police treatment of minorities.

"The public deserves to know what happened with that grand jury and why what we saw with our eyes did not match the failure to indict those responsible for Eric Garner's death," James said in a statement.

Garner's relatives were disappointed in the decision, as they feel releasing the information is the only way to address their doubts about the fairness of the grand jury process, said one of their lawyers, Josh Moskovitz.

A bystander's video showed the unarmed Garner repeatedly pleading, "I can't breathe!" as Officer Daniel Pantaleo took him to the ground with an arm around his neck. Pantaleo was attempting to arrest Garner on suspicion of selling untaxed cigarettes on a Staten Island street.

The medical examiner ruled that Garner was killed by neck compressions from the chokehold and his positioning during police restraint. The New York Police Department bans chokeholds; Pantaleo said he instead used a permissible takedown maneuver.

Former Staten Island District Attorney Daniel Donovan, who took the case to the grand jury before being elected to Congress this May, successfully asked a judge last winter to release such details as the number of witnesses. But his and other prosecutors' offices have argued against releasing the transcripts, noting that grand jurors and witnesses expect confidentiality to assure them they won't be subjected to public criticism for participation.

Acting Staten Island DA Daniel Master declined to comment.

The request came amid an ongoing debate over whether lawmakers should make grand juries more transparent, particularly in police killing cases. The NYCLU and others argued that releasing the Garner case transcripts would help lawmakers decide what to do.

But appeals judges said it wasn't clear how the information "would inform legislative debate beyond the facts that are already publicly known of the case."